Dentifrice comprising insoluble sodium metaphosphate and a cadmium, tin, zinc, manganese or iron compound to inhibit calcium ion sequestering



Delaware N Drawing. Filed Feb. 20, 1956, Ser. No. 566,333

11 Claims. (Cl. 167-93) This invention relates to polishing compositions suitable for use as a dentifrice base and particularly to those compositions which contain the insoluble form of sodium metaphosphate as an ingredient thereof.

An object of the present invention is the provision of an improved dentifrice.

The use of the so-called insoluble form of sodium metaphosphate in finely divided form has been proposed as a dentifrice. This material, however, has a definite, though small, solubility in water or other aqueous liquids. Further, it has been found that the soluble part of the so-oalled insoluble metaphosphate has a definite solubilizing action on certain lime salts.

I have now found that by incorporating small amounts of compounds of cadmium, tin, zinc, manganese, aluminum and iron, particularly those of aluminum and zinc, which furnish available dissolved aluminum or zinc ions, it becomes possible to inhibit the dissolving action of the soluble portion of the insoluble form of sodium metaphosphate.

'Ilhe specific metal compounds which I mayadd to the insoluble sodium metaphosphate may either be soluble or insoluble in water or related aqueous solutions. Exam ples of suitable salts, representative of all of the above class, but exemplified specifically with respect to the aluminum' and zinc compounds are the oxides A1 0 or ZnO, or hydrated oxides Al O -3H O, the chlorides AlCl or ZnCl the sulfates Al (SO or ZnSO the citrates A1C6H5O7, or Zn (C H O the phosphates such as the orthophosp-hates A1PO or Zn (PO etc. Other molec ular forms and various hydrated compounds may also be employed. These additive materials may be incorporated in the proportion of 0.05% to 50% by weight as a slurry or dry powder with the insoluble metaphosphate for incorporation into a tooth powder or tooth pastel The proportion of such metal salts is not critical, and hence, may be varied in order to furnish the desired inhibiting action.

Particularly useful salts in this relationship are the fluorides of cadmium, tin, zinc, manganese, aluminum and iron, a preferred group being aluminum fluoride, AlF or zinc fluoride, ZnF These fluorides concomitantly provide an agent elfective in reducing the sequestering action of the soluble portion of the sodium metaphosphate, while also providing fluoride in a form which is useful in formulated dentifrices. All of the fluoride compounds described above are effective in reducing the sequestering action of insoluble sodium meta-phosphate.

If a fluoride type dentifrice is desired, a soluble fluoride salt maybe used, for example stannous fluoride employed at about 0.1 weight percent, calculated as fluoride. In general the weight percentage of the fluoride, including the preferred group of aluminum fluoride, stannous fluoride and sodium fluoride, present as the salt, is in the range of 0.5% to 1%.

An advantage of the present use of fluorides with the above-described group of metal salts is the improvement United States Patent 0 3,095,356 Patented June 25, 1963 of fluoride uptake by the teeth. Soluble fluorides are found to be taken up to a greater extent when these metal salts are also present with the fluoride. The proportion of the fluorides, such as aluminum, tin, or sodium fluoride employed in the practice of the present invention is in the range of 0.05 to 1% by weight of the dentifrice composition. However, the total proportion of metal compounds of the group of cadmium, tin, zinc, manganese, aluminum and iron which are present in the dentifrice is within the broader range of 0.05 to 50 weight percent.

According to one of the present theories as to the molecular aggregation of phosphate salts, the insoluble sodium metaphosphate containing the usual impurities, may exist as a chain-type of molecular structure, and also in the form of relatively short-chain polyphosphates. According to this theory, the presently employed metal compounds control the sequestering action of polyphosphates, thereby controlling the type of molecular structures present in an aqueous solution or dispersion in which the said insoluble sodium metaphosphate may "be present. However, the above discussion is not necessarily a complete explanation of the mode of action of the presently employed metal compounds, for example, and the present invention is not restricted thereto.

The invention in general contemplates the use of finely divided insoluble sodium inetaphosphate as a component of a dentifrice base. The combination also includes a suflicient amount of the above compound of a metal selected from the group consisting of cadmium, tin, zinc, manganese, aluminum, and iron to inhibit the calcium ion sequestering effect, characteristic of the said sodium met-aphosphate. A preferred group of compounds utilized for such inhibition are the compounds of aluminum and zinc, a still vmore preferred embodiment being aluminum hydrate, i.e., Al(OH) This compound which is also known as aluminum hydroxide is employed in the present dentifrice composition. It is also found that this compound provides a secondary advantage in dentifrice compositions, inasmuch as the aluminum hydrate provides a highly desirable whitening effect which improves the tinctorial power and opacity of the toothpaste.

The above-described inhibiting compositions utilized together with the insoluble sodium metaphosphate are also of great utility in combination with various fluorides which are employed in many dentifrice compositions. it has been a disadvantage of many polishing agents conventionally employed in dentifrices that certain polishing agents are incompatible with fluorides. For example, calcium compounds readily'precipitate the highly insoluble calcium fluoride which thus prevents the fluoride ion from being eflective in the use of such toothpowders and toothpastes containing the same. The use of the presently described metal compounds, for example aluminum hydrate as described above, in combination with insoluble sodium metaphosphate, completely eliminates the possibility of precipitating fluoride ions which may be present in combination with these two components. Accordingly, the combination of the sodium metaphosphate and aluminum hydrate provides a highly eflicacious dentifrice base which may be formulated with conventional fluoride compounds. With regard to the other compounds described above, the following fluorides exhibit substantial solubility in a precipitating system such as a toothpaste, .so that precipitation and consequent loss of the fluorideis avoided: cadmium fluoride, stannous fluoride, zinc fluoride, manganous fluoride, aluminum fluoride, ferrous fluoride, and ferric fluoride.

Soluble calcium salts and insoluble calcium orthophosphates, as set forth above, are undesirable in fluoride dentifrices because of reaction with the fluoride to produce insoluble calcium fluoride or fluorapatite which renders the fluoride content unavailable to the teeth. Similar disadvantages are found to arise in the use of magnesium compounds. Furthermore, the use of magnesium compounds in the presence of insoluble sodium metaphosphate has the disadvantage that the magnesium salts cause a setting up or solidification in the toothpaste tube.

Another advantage resulting from the use of the abovedescribed compounds of cadmium, tin, zinc, manganese, aluminum, and iron in combination with sodium metaphosphate in fluoride dentifrices is the reduced corrosivity towards metal containers. Prior art fluoride dentifrices may be corrosive towards metal containers such as tin cans utilized to contain toothpowders, or tin, aluminum, or lead tubes provided for the dispensing of toothpastes. Aluminum hydrate, for example, when used in the present combination compositions containing the said metal salts together with the insoluble sodium metaphosphate and a specific fluoride exhibit less corrosivity towards the above-described metal containers than do the same fluoride compounds such as sodium fluoride utilized alone.

Specific examples illustrative of the present invention are set forth below.

Example 1 One hundred g. of insoluble sodium metaphosphate were extracted with distilled water in order to remove the soluble portion. The water extract (after separation from the insoluble metaphosphate) was then treated with about 50 ml. of a 10% solution of zinc acetate at room temperature. It was found that a filterable precipitate formed almost immediately, representing the zinc salts of short-chain polyphosphates. The insoluble sodium metaphosphate was thus reduced in sequestration ability.

Example 2 One hundred g. of insoluble sodium metaphosphate was treated with 100 ml. of distilled water in order to extract the minor proportion of soluble components representative of shortchain polyphosphates. The water extract (after separation from the insoluble metaphosphate) was then treated with a 50 ml. portion of aluminum sulfate (10% solution) at room temperature. It was found that a gel was formed which could be precipitated on heating to 60 C. for 10 minutes. This gel, corresponding to the alumi num salt of the polyphosphate components present, rendered the insoluble sodium metaphosphate free from a solubilizing effect on insoluble calcium salts dispersed or present in the solution.

Example 3 Example 4 A toothpowder was prepared utilizing the following formulations by weight, and also indicating the range of variation of the components:

Range, percent (1) Insoluble sodium metaphosphate, 400 grams 36-97 (2) Hydrated aluminum oxide (Reynolds C-33 grade), 21 grams 1-50 (3) Detergent (sodium lauryl sulfate), 20 grams 2-8 (4) Saccharine, 1 gram 0.05-2

(5) Flavoring (essential oil), 4 grams .05-2

The detergents employed, in general, are of the alkyl sulfate type. However non-soap synthetic detergents are of utility in this relationship in the present invention to provide a non-soap wetting and foaming agent in the dentifrice.

The toothpaste was prepared by combining 450 parts by weight of powder prepared according to the above formulation with 550 parts of an elixir prepared utilizing the formulation below:

Range, percent The two formulations are found to yield satisfactory V dentifrices which possess a long shelf life without setting up in the tube. In general, the proportion of the powder components is from to by weight in order to obtain smooth paste.

'If a fluoride dentifrice is desired, a soluble fluoride salt, for example aluminum fluoride, is used at about 0.1%, calculated as fluoride (e.g., 0.939 in the above formulation). In general the weight percentage of the fluoride as a salt is preferred to be in the range of 0.05 to 1%.

What I claim is:

1. A dentifrice polishing composition comprising finely divided insoluble sodium metaphosphate normally containing calcium ion sequestering soluble phosphates and a sufiicient amount of a compound selected from the group consisting of cadmium halides, cadmium phosphates, cadmium sulphates, cadmium oxides, zinc halides, zinc phosphates, zinc sulphates, zinc oxides, manganese halides, manganese phosphates, manganese sulphates,

manganese oxides, iron halides, iron phosphates, iron sulphates, iron oxides, tin oxides, tin sulphates, tin phosphates and tin halides other than fluorides, to inhibit said calcium ion sequestering effect.

2. A dentifrice polishing composition according to claim 1 additionally containing from about 0.05% to about 1% by Weight of a soluble fluoride selected from the group consisting of aluminum fluoride, stannous fluoride and sodium fluoride.

3. A dentifrice polishing composition comprising finely divided insoluble sodium metaphosphate containing water-soluble polymeric sodium phosphates, which soluble phosphates possess a calcium ion sequestering effect, and an amount of a zinc halide suflicient to inhibit the said calcium ion sequestering effect.

4. A dentifrice polishing composition comprising finely divided insoluble sodium metaphosphate containing water-soluble polymeric sodium phosphates, which soluble phosphates possess a calcium ion sequestering effect, and an amount of a zinc phosphate sufficient to inhibit the said calcium ion sequestering effect.

5. A dentifrice polishing composition as in claim 4 containing from 0.05 to 50% of said zinc phosphate.

6. A dentifrice polishing composition comprising finely divided insoluble sodium metaphosphate containing- Water-soluble polymeric sodium phosphates, which soluble phosphates possess a calcium ion sequestering effect, and an amount of zinc sulphate sufficient to inhibit the said calcium ion sequestering effect.

7. A dentifrice polishing composition comprising finely divided insoluble sodium metaphosphate containing water-soluble polymeric sodium phosphates, which soluble phosphates possess a calcium ion sequestering effect, and an amount of zinc oxide sufficient to inhibit said calcium ion sequestering effect.

8. A dentifrice polishing composition comprising finely divided insoluble sodium metaphosphate containing water-soluble polymeric sodium phosphates, which soluble phosphates possess a calcium ion sequestering effect, and an amount of zinc oxide in the range of from 0.05% to 50.0% by weight relative to the said sodium metaphosphate.

9. A dentifrice polishing composition containing the followmg components by weight:

Percent Insoluble sodium metaphos hate containing water soluble polymeric sodium p osphates which possess a calcium ion sequestering effect A compound selected from the group consisting of cadmium halides, cadmium phosphates, cadmium sulphates, cadmium oxides, zinc halides, zinc phosphates, zinc sulphates, zinc oxides, manganese halides, manganese phosphates, manganese sulphates, manganese oxides, iron halides, iron phosphates, iron sulphates, iron oxides, tin oxides, tin sulphates, tin phosphates, and tin halides other than fluorides 1-5 Organic detergent 28 Saccharin 0.052 Flavoring other than saiccharin 0.05'2

10. A dentifrice polishing composition containing the :following components by weight:

Percent Insoluble sodium metaphosphate containin water sol- 'uble polymeric sodium phosphates whic possess a calcium ion sequestering efl'fect A compound selected from the group consisting of cadmium halides, cadmium phosphates, cadmium sulphates, cadmium oxides, zinc halides, zinc phos Ehates, zinc sulphates, zinc oxides, manganese alides, manganese phosphates, manganese sulphates, manganese oxides, iron halides, iron phosphates, iron sulphates, iron oxides, tin oxides, tin sulphates, tin phosphates, and tin halides other than fluorides 1-50 Organic detergent 28 Saccharin 0.052 Flavoring other than saccharin 0052 Soluble fluoride 0205-1 11. A dentifrice polishing composition containing about in combination with an elixir comprising the following components by weight:

Percent Glycerine 29-59 Water 59-38 Bodying agents selected from the group consisting of gum karaya and gum tragacanth 0.5-4

References Cited in the file of this patent UNITED STATES PATENTS 1,529,486 Kaemmerling et a1. Mar. 10, 1925 2,086,867 Hall July '13, 1937 2,216,821 Long Oct. 8, 1940 FOREIGN PATENTS 158,717 Australia Sept. 9', 1954 OTHER REFERENCES 

1. A DENTIFRICE POLISHING COMPOSITION COMPRISING FINELY DIVIDED INSOLUBLE SODIUM METAPHOSPHATE NORMALLY CONTAINING CALCIUM ION SEQUESTERING SOLUBLE PHOSPHATES AND A SUFFICIENT AMOUNT OF A COMPOUND SELECTED FROM YHE GROUP CONSISTING OF CADMIUM HALIDES, CADMIUM PHOSPHATES, CADMIUM SIULPHATES, CADMIUM OXIDES, ZINC HALIDES, ZINC PHOSPHATES, ZINC SULPHATES, ZINC OXIDES, MANGANESE HALIDES, MANGANESE PHOSPHATES, MANGANESE SULPHATES, MANGANESE OXIDES, IRON HALIDES, IRON PHOSPHATES, IRON SULPHATES, IRON OXIDES, TIN OXIDES, TIN SULPHATES, TIN PHOSPHATES AND TIN HALIDES OTHER THAN FLUORIDES, TO INHIBIT SAID CALCIUM ION SEQUESTERING EFFECT. 